The castle sits at the top of the hill in the oldest part of the city, above the Priory Church, and dominates the skyline. It has Norman origins — the keep dates from the 12th century — but most of what you see is medieval and later, including the grand John of Gaunt gatehouse. The castle is still a functioning Crown Court, which means access to parts of the interior is controlled, but guided tours take in the historic courtroom where the Pendle Witches were tried in 1612, the cells, the drop room used for executions, and the dungeons.
Lancaster Castle served as a working prison until 2011, making it one of the longest-serving penal facilities in England. The tour isn't heritage dressing — people were held and hanged here well within living memory. The haunted reputation follows naturally: the castle runs popular evening ghost tours if that's your thing.
Tours run most days; check the castle website for times. The Crown Court schedule affects which areas are open.